Own a few superlux HD681.. but this thing make my ear sweat like crazy (im a big guy, with huge head). But still, for the price - AMAZING sound and semi open design is great..

1 - I open the padding and found that the filter was too thin thin for my liking, so i cut out some cloth and lay it on the inside of the filter. This took out a few treble that i don't really like. Of course this is mostly preferential.

2 - I think the sponge on the padding is ok, but the pleather surface itself is quite hard, so had the genius idea of flipping it inside out
i was absolutely amazed by the result. The inside surface of HD681 was softer, and helps a lot with the sweating. Somehow it felt nicer too (on my ear at least)

Anyway. Just wanted to share just in case anyone else has same issue.